The specific epithet microspermum refers to the species' small spores.

It is macroscopically identical to Psilocybe cubensis but has smaller spores.

Molds reproduce through producing very large numbers of small spores, which may contain a single nucleus or be multinucleate.

The species is distinguished from the closely related C. aeruginosum by having smaller spores.

On the rock's flat surface lay a root, wet, covered with small open spores.

C. herbarum has smaller spores and a pale-yellowish spore print.

It is best distinguished microscopically by its smaller spores that lack a germ pore.

It has somewhat smaller spores than P. semilanceata, typically 8-9.9 by 5.5-7.7 μm.

However, A. subrufescens produces smaller spores, sized 6-7.5 by 4-5 m.

In addition to its different distribution, it can be distinguished from T. plumbeoviolaceus by its smaller spores.